As well, OTT video distribution leverages adaptive bit rate (ABR) encoding of the segmented video files so that the service can tradeoff network performance and video quality to maximize the users experience.  If network issues are such that the segmented files cannot be downloaded fast enough to keep the video operating smoothly, then a lower bitrate version of the files is requested allowing the video playout to continue smoothly, albeit at a lower quality resolution.

Monitoring the video service

Video services, much like voice services, are dependent on a low latency, error free connection to ensure a high quality of service.  Being able to continuously monitor the quality of a video signal being received by a customer is critical to maintaining a good quality of experience.  Failure to do so will likely result in the loss of both customers and revenue.

There are several ways of monitoring the quality of a video service, depending on the type of video being used.  Traditional broadcast video, the kind you might get from a satellite TV provider or over-the-air transmission, rely on passive monitoring only.  For these methods, it is sufficient to have a test set with an appropriate receiver which can then analyze the received signal for such things as signal strength, encoding errors, and missing channels.  Since these traditional methods broadcast "all channels, all the time", there is no need for the test set to request content.  Key performance indicators (KPI) for the received broadcast signals can be generated and sent to a video operations center to allow the provider to see how the service is behaving and take appropriate action if warranted.

IP video services, on the other hand, are not broadcast services.  They rely on signaling from the receiver to request specific content.  Additionally, because the distribution is packet based, IP video is susceptible to a variety of other service quality and network issues; therefore, in addition to assuring the video and audio content of the received signal, IP video services, including IPTV and OTT video, need to employ active monitoring to request specific content from the application server and verify the receipt of that content before it can analyze the quality of the video received. 

Additionally, because IP video relies on internet protocols for streaming live traffic, in the case of IPTV, or delivering video file segments, in the case of OTT, any testing strategy also needs to account for the content encoding as well as the decoding.  OTT video further complicates this because of its reliance on ABR encoding, video file segmenting and the use of CDNs for distribution.  To address all these IP video issues, the CSP needs a comprehensive active video assurance strategy to ensure complete visibility of the service, whatever video technology is being used.

Best practices in IP Video distribution and monitoring dictate that testing of video services should be done wherever the content is encoded, received, stored and watched.  Doing this not only ensures the delivered video product is of good quality, but if there is an issue, isolating the location and cause is much quicker and the service network can be modified to bypass issues.

In the case of OTT video, monitoring should also take place at the video origin server, where the content is encoded and segmented, as well as at various points along the distribution path, including at the hand-off to the CDN, the hand-off to the local CSP, the hand-off to access network, and the hand-off to the customer. 

Similarly, IPTV video services need video and audio assurance at the point of content origination and should also include delivery assurance at all key network interface points to fully monitor the delivery of quality services to the customer.

To ensure a complete and robust monitoring solution, the family of video assurance equipment used should be able to support not only all the variations of video distribution technology, but should also provide a common surveillance platform to manage the entire video assurance strategy and provide the CSP with a unified view of the health of their video service, regardless of technology.